Use of ultrasound for pasteurization and sterilization of liquids is known. For example, in an existing method ultrasonic waves are emitted into a fluid with the goal of sterilizing the fluid, and killing and inactivating organisms within the fluid. In existing methods, ultrasonic waves are typically emitted into the laminar flow of the treated liquid, with an ultrasound transducer being mounted on a tank wall, where the laminar flow is arranged.
However, use of ultrasound treatment of fluids for their sterilization or pasteurization inside a dispenser nozzle presents different challenges than those addressed by existing apparatuses and methods. It would be desirable to achieve high efficiency of cavitation excitation in a liquid flow and a more compact design so that ultrasound treatment of fluids can be used for sterilization or pasteurization inside a dispenser nozzle.